Sunday, June 19, 2016

In this article we shall discuss about two powerful Linux
utilities that are used for sharing file/folder to network computers
that are scp and rsync. scp
allows you to simply copy directories or files from/to any remote
destination whereas the rsync, besides simply copying files also acts as
a synchronising tool that would synchronise the
changes between source and destination. The discussion below is about
their usage and various parameters that can be used along with to
increase speed and security.

What Is SCP?

The SCP is a network protocol based on the BSD, RCP protocol. It supports file transfer over a network computers using Secure Shell (SSH).
With SCP a client can send files to another client or server on the
same network. It can also request or Download files from a server.

If user wants to share multiple files over a network computer then there
are two ways to accomplish that. User can either specify each file in
the command and then provide the destination path. The second method is
that user can save all the files in one folder and can share the entire
folder over the network computer. Both the methods have been mentioned
below. You can use anyone you like.

Install OpenSSH Server In Linux

OpenSSH is required for doing Linux data transfer over network. I
noticed that it's not already installed in some Linux distributions so
in that case, the commands result in errors. So install OpenSSH server
before you go ahead and share files using SCP.

Install OpenSSH Server

Syntax - How To Share Files Over A Network Computer?

SCP Syntax

Example - If you want to share a file name "myMovieList.txt" to a remote host(192.168.1.102), you can use the following command based on the above syntax.

SCP Linux File Sharing

To copy file from remote machine to your local machine

Copy file from remote machine to local machine

To copy multiple files, provide space separated list of files and at the last destination path

SCP - Copy multiple files

Using SCP Parameters For More File Sharing Options

You can use scp command with certain optional parameters that help you in faster copying and/or secure data transfer.

r : To copy directory you have to use parameter r to recursively copy the contents.

​The r command makes it very simple to
transfer multiple files contained in a single folder. It's one of the
best methods to do quick and secure Linux file sharing over network
computers.

'r' Parameter to copy folder to a host computer

P : To send out file on machine with different port

​By default, scp shares file over network computers through port 22. In many cases, you would want to use another port then you can P parameter to use another port for folder sharing.

'P' Parameter to share files on host computer through a different port

​c : Change Encryption algorithm

By default, scp uses Triple-DES cipher to encrypt
data before transferring it. You can use other ciphers like blowfish
(which has higher performance over default one).

'c' Change Encryption Algorithm

C : To transfer even faster you can use
compression parameter that would compress the data while transferring
and auto decompress it on the destination.

NOTE: No need to decompress the file on the destination.

What Is rsync?

​Rsync is helpful in sharing files annd folders and synchronising files
and folders. Unlike SCP, rsync transfers only differences between source
and destination files/folders. It uses compression and decompression by
default and hence is faster than SCP. Once you get familiar with it,
it'll save your a lot of time.

Install rsync In Linux

Install rsync in Linux

Syntax To Sync Folder Between Network Computers

Syntax

With rsync user can synchronize two folders existing over network
computers. To transfer/sync folder from local to remote host, use the
following command -

​
only rsync files/folders starting with S.
​--delete : delete the directory if it doesn't exist at source but exists at the destination.--max-size : max transfer size limit. [eg: --max-size='2000k']--remove-source-files : remove files at source after sync--bwlimit : limit bandwidth for transfer [--bwlimit=1000] (limit by 1000 bps)
If you are unsure of rsync command result, you can also do dry run with command : --dry-run.

Conclusion

Both the linux utilities are useful in sharing files over network
computers. rsync being more efficient since it transfers only
differences and compressed data by default. That's all for now. You can
explore man pages for more. Do leave suggestions, comments or questions in the comment section below.